Horton

Re: Estimating HugePages Requirements?

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Magnus Hagander <magnus@hagander.net>
Cc: Julien Rouhaud <rjuju123@gmail.com>, Don Seiler <don@seiler.us>, pgsql-admin <pgsql-admin@postgresql.org>
Date: 2021-06-09T19:28:45Z
Lists: pgsql-hackers 
Magnus Hagander <magnus@hagander.net> writes:
> On Wed, Jun 9, 2021 at 9:15 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Just try to start the server and see if it complains.

> Well, I have to *stop* the existing one first, most likely, otherwise
> there won't be enough huge pages (or indeed memory) available.

I'm not following.  If you have a production server running, its
pg_shmem_allocations total should already be a pretty good guide
to what you need to configure HugePages for.  You need to know to
round that up, of course --- but if you aren't building a lot of
slop into the HugePages configuration anyway, you'll get burned
down the road.

			regards, tom lane

Commits

  1. Silence extra logging when using "postgres -C" on runtime-computed GUCs

  2. doc: Improve postgres command for shared_memory_size_in_huge_pages

  3. Introduce GUC shared_memory_size_in_huge_pages

  4. Support "postgres -C" with runtime-computed GUCs

  5. Make shared_memory_size a preset option

  6. Introduce GUC shared_memory_size

  7. Move the shared memory size calculation to its own function

  8. Add new GUC, max_worker_processes, limiting number of bgworkers.